Zoom lens and imaging device having the same

Abstract

To provide a small-sized zoom lens having lens groups with small diameters.SOLUTION: A zoom lens comprises a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, an intermediate group having one or more lens groups, and a final lens group having a positive refractive force, which are arranged in order from an object side to an image side. In zooming, the interval between the adjacent lens groups changes. A lens arranged on the most object side, of lenses included in the second lens groups, has a concave surface directed to the object side. In zooming from a wide-angle end to a telephoto end, the interval between the first lens group and the second lens group increases. When the distortion amount at the wide-angle end is defined as Distw[%], and the maximum half angle of view at the wide-angle end as ωw [degrees], predetermined conditional expressions are satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a zoom lens and is suitable for imaging devices such as digital video cameras, digital still cameras, broadcast cameras, silver halide film cameras, and surveillance cameras. [Background technology]

[0002] In recent years, there has been a demand for miniaturization of zoom lenses used in imaging devices. As a zoom lens that satisfies this requirement, a positive-lead type zoom lens is known in which the lens group with the most positive refractive power is arranged closest to the object. Patent Document 1 discloses a positive-lead type zoom lens consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a fourth lens group arranged sequentially from the object side to the image side. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-118127 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In the positive-lead type zoom lens described above, various mechanisms such as the image stabilization mechanism for correcting image shake and the mechanism for moving the lens group during focusing and zooming are positioned closer to the image than to the lens group closest to the object. If the diameter of the lenses in the lens group positioned closer to the image than to the lens group closest to the object becomes large, the aforementioned mechanisms will also become larger, resulting in a larger zoom lens. Therefore, in order to achieve miniaturization of zoom lenses, it is necessary to reduce the diameter of each lens group by appropriately setting the refractive power and arrangement of the lens groups that make up the zoom lens.

[0005] Therefore, the object of the present invention is to provide a compact zoom lens having a small-diameter lens group. [Means for solving the problem]

[0006] A zoom lens as one aspect of achieving the above objective comprises a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, an intermediate group consisting of one or more lens groups, and a final lens group having positive refractive power, arranged in order from the object side to the image side, wherein the distance between adjacent lens groups changes during zooming, the zoom lens has an aperture diaphragm, the first lens group consists of a negative lens, a positive lens, and a positive lens arranged in order from the object side, the intermediate group includes one or more lens groups with negative refractive power, the maximum half-angle at the wide-angle end is ωw [degrees], the focal length of the first lens group is f1, the focal length of the final lens group is fLR, the distance along the optical axis from the object-side lens surface of the lens closest to the object at the wide-angle end to the aperture diaphragm is LS1, and the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end is LS2 The focal length of the third lens group is set to f3, and the focal length of the second lens group is set to f2 In this case, it is characterized by satisfying the following conditional expression. 0.1 < ωw < 25.0 1.00 <fLR×LS2 / (f1×LS1)<3.00 1.00 <fLR / f3<5.00 -7.00 <f1 / f2<-3.00

[0007] Furthermore, as another aspect for achieving the above objective, a zoom lens comprises a first lens group having positive refractive power, a second lens group having negative refractive power, an intermediate group consisting of one or more lens groups, and a final lens group having positive refractive power, arranged sequentially from the object side to the image side, wherein the spacing between adjacent lens groups changes during zooming, and the second lens group is characterized by having positive lenses. [Effects of the Invention]

[0008] According to the present invention, a small zoom lens having a small-diameter lens group can be provided.

Brief Description of the Drawings

[0009] [Figure 1] Lens cross-sectional view at the wide-angle end of the zoom lens of Example 1 [Figure 2] Longitudinal aberration diagrams of the zoom lens of Example 1 at (A) wide-angle end and (B) telephoto end [Figure 3] Lens cross-sectional view at the wide-angle end of the zoom lens of Example 2 [Figure 4] Longitudinal aberration diagrams of the zoom lens of Example 2 at (A) wide-angle end and (B) telephoto end [Figure 5] Lens cross-sectional view at the wide-angle end of the zoom lens of Example 3 [Figure 6] Longitudinal aberration diagrams of the zoom lens of Example 3 at (A) wide-angle end and (B) telephoto end [Figure 7] Lens cross-sectional view at the wide-angle end of the zoom lens of Example 4 [Figure 8] Longitudinal aberration diagrams of the zoom lens of Example 4 at (A) wide-angle end and (B) telephoto end [Figure 9] Lens cross-sectional view at the wide-angle end of the zoom lens of Example 5 [Figure 10] Longitudinal aberration diagrams of the zoom lens of Example 5 at (A) wide-angle end and (B) telephoto end [Figure 11] Schematic diagram of the imaging device of the embodiment

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that each drawing may be drawn at a scale different from the actual for convenience. In each drawing, the same members are denoted by the same reference numerals, and redundant explanations are omitted. Further, in the following embodiments, the wide-angle end and the telephoto end refer to the zoom positions when the lens group for zooming is located at both ends of the range where it can move on the optical axis in terms of mechanism.

[0011] Figs. 1, 3, 5, 7, and 9 are cross-sectional views at the infinite focus of the wide-angle end of the zoom lens L0 according to Embodiments 1 to 5, respectively. In each cross-sectional view, IP represents the image plane. The zoom lens L0 according to each embodiment is used in an imaging device, and an imaging surface of a solid-state imaging device (photoelectric conversion element) such as a CCD sensor or a CMOS sensor is disposed at the position of the image plane IP. Note that the zoom lens of each embodiment may be used as an imaging optical system of a silver halide film camera. In this case, a photosensitive surface corresponding to the film surface is disposed on the image plane IP. Also, in each cross-sectional view, SP represents an aperture stop that determines (limits) the light beam of the open F-number.

[0012] In each cross-sectional view, the left side is the object side (front side), and the right side is the image side (rear side). Note that the zoom lens L0 according to each embodiment may be used as a projection lens such as a projector. In this case, in each cross-sectional view, the left side is the screen side, and the right side is the side of the projected image. Also, in each cross-sectional view, the i-th lens group arranged in the i-th position from the object side toward the image side is represented by Li. In the zoom lens L0, the interval between adjacent lens groups changes during zooming. That is, in the present specification, the lens group indicates a group of lenses that move integrally during zooming or a group of lenses that do not move during zooming. Note that the lens group may be composed of one lens or a plurality of lenses. Also, the lens group may include an aperture stop.

[0013] The arrows (solid lines) shown in each cross-sectional view represent the movement trajectories of the respective lens groups during zooming from the wide-angle end to the telephoto end of the zoom lens L0. Also, the arrows (broken lines) shown in each cross-sectional view represent the movement trajectories of the respective lens groups during focusing from infinity to a short distance.

[0014] Figs. 2, 4, 6, 8, and 10 are longitudinal aberration diagrams at the infinite focus of the wide-angle end of the zoom lens L0 according to Embodiments 1 to 5, respectively. In each longitudinal aberration diagram, a spherical aberration diagram, an astigmatism diagram, a distortion diagram, and a chromatic aberration diagram are represented in order from the left side. Also, in each longitudinal aberration diagram, (A) represents the longitudinal aberration diagram of the wide-angle end, and (B) represents the longitudinal aberration diagram of the telephoto end.

[0015] In each longitudinal aberration diagram, Fno is the F-number and ω is the half-angle of view (degrees). In the spherical aberration diagram, the solid line shows the amount of spherical aberration with respect to the d-line (wavelength 587.6 nm), and the dashed line shows the amount of spherical aberration with respect to the g-line (wavelength 435.8 nm). In the astigmatism diagram, ΔS (solid line) shows the amount of astigmatism in the sagittal image plane, and ΔM (dashed line) shows the amount of astigmatism in the meridional image plane. In the distortion diagram, the solid line shows the amount of distortion with respect to the d-line. In the chromatic aberration diagram, the dashed line shows the amount of chromatic aberration with respect to the g-line.

[0016] Next, we will describe the characteristic configuration of the zoom lens L0 according to Examples 1 to 5.

[0017] The zoom lens L0 according to each embodiment consists of a first lens group L1 having positive refractive power, a second lens group L2 having negative refractive power, an intermediate group LM having one or more lens groups, and a final lens group LR having positive refractive power, all arranged in order from the object side to the image side.

[0018] In the zoom lens L0 according to each embodiment, the final lens group LR, which is positioned closest to the image, has a positive refractive power. This strongly generates barrel distortion, allowing the position of the exit pupil to move towards the object. As a result, the ray height of the off-axis light rays incident on the second lens group L2 can be reduced, thus allowing the diameter of the second lens group L2 to be reduced.

[0019] In the zoom lens L0 according to each embodiment, the distance between the first lens group L1 and the second lens group L2 increases when zooming from the wide-angle end to the telephoto end. This reduces the positive refractive power of the first lens group L1, thereby reducing the occurrence of spherical aberration at the telephoto end. Furthermore, at the telephoto end, the ray height of the on-axis marginal rays incident on the second lens group L2 can be reduced, allowing the second lens group L2 to have a smaller diameter.

[0020] The above-described characteristic configuration makes it possible to provide a compact zoom lens with a small-diameter lens group.

[0021] Next, we will describe the conditions that are preferable to satisfy in the zoom lens L0 according to each embodiment.

[0022] In the zoom lens L0 according to each embodiment, it is preferable that the lens located closest to the object among the lenses included in the second lens group L2 has a concave surface facing the object. This suppresses the occurrence of spherical aberration and coma aberration at the wide-angle end, while strongly generating barrel distortion and shifting the position of the exit pupil toward the object. As a result, the ray height of off-axis light rays incident on the second lens group L2 can be reduced, allowing the second lens group L2 to have a smaller diameter.

[0023] In the zoom lens L0 according to each embodiment, it is preferable that the second lens group has a positive lens. By converging the light incident on the second lens group with the positive lens, the diameter of the lens group positioned closer to the image than the second lens group can be made smaller.

[0024] In the zoom lens L0 according to each embodiment, it is preferable that the third lens group L3 has a positive refractive power. As a result, the light rays diverged by the second lens group L2 converge in the third lens group L3, making it possible to reduce the diameter of the lens group positioned closer to the image than the third lens group L3.

[0025] In each embodiment, the intermediate group LM of the zoom lens L0 preferably has at least one lens group having a negative refractive power. This makes it possible to reduce field curvature across the entire zoom range.

[0026] In each embodiment of the zoom lens L0, it is preferable that the second lens group L2 is immovable relative to the image plane for zooming. This reduces the relative positional deviation due to manufacturing errors between the first lens group L1, which moves during zooming, and the coma aberration that occurs when eccentric at the telephoto end.

[0027] In each embodiment, the zoom lens L0 preferably has a negative lens among the lenses included in the second lens group L2 that is positioned closest to the object. This allows off-axis light rays incident on the second lens group L2 to be gently bent, thereby reducing coma aberration and astigmatism at the wide-angle end.

[0028] In each embodiment, the zoom lens L0 preferably has the second lens group L2 moved in a direction that includes a component perpendicular to the optical axis for vibration isolation, such as image shake correction. In a positive lead type zoom lens, the light rays converge in the first lens group L1, so by making the second lens group L2 a vibration isolation group, the vibration isolation mechanism can be made smaller. Furthermore, other lens groups besides the second lens group L2 may also be moved for vibration isolation.

[0029] In the zoom lens L0 according to each embodiment, barrel distortion is introduced in order to reduce the diameter of the second lens group L2. In order to maintain optical performance while reducing the diameter of each lens group of the zoom lens L0, it is preferable to suppress the occurrence of various aberrations in the zoom lens L0 or to correct various aberrations well.

[0030] Therefore, in order to achieve a smaller diameter for each lens group while maintaining high optical performance, it is preferable to appropriately set the distortion amount and half-angle of view of the zoom lens L0. Specifically, it is preferable that the zoom lens L0 in each embodiment satisfies the following conditions (1) and (2). -20.0 <Distw<-4.5 (1) 0.1 < ωw < 25.0 (2)

[0031] Conditional equation (1) defines the amount of distortion at the maximum image height when the zoom lens is in focus at the wide-angle end. Here, when the ideal image height in the central projection method is y and the actual image height is yp, the amount of distortion at an arbitrary image height at the wide-angle end, Distw[%], is defined by the following equation. Distw[%]=((yp-y) / y)×100

[0032] In the central projection method, the ideal image height y is defined by the following equation, where f is the focal length of the zoom lens L0 and θi is the half-angle of view of the actual rays at an arbitrary image height. y = f × tanθi

[0033] If the upper limit of condition (1) is exceeded, barrel distortion is suppressed, and the position of the exit pupil moves towards the image side. As a result, the ray height of off-axis light rays incident on the second lens group L2 increases, and the lens diameter of the second lens group L2 increases, which is undesirable. If the lower limit of condition (1) is exceeded, the absolute value of the radius of curvature of the lens surface closest to the object in the second lens group L2 becomes small, and spherical aberration and coma aberration occur strongly at the wide-angle end, which is undesirable.

[0034] Conditional equation (2) defines the half-angle of view (maximum half-angle of view) at the maximum image height at the wide-angle end of the zoom lens. In the embodiment of the present invention, when Y is the radius of the image circle, and fw is the focal length of the zoom lens L0 at the wide-angle end, the half-angle of view ωw [degrees] is defined by the following equation. ωw = arctan(Y / fw)

[0035] If the upper limit of condition (2) is exceeded, the ray height of the off-axis rays incident on the subsequent lens group LR becomes large, making it difficult to reduce the diameter of the final lens group LR, which is undesirable. If the lower limit of condition (2) is exceeded, the zoom lens L0 cannot obtain sufficient magnification, which is also undesirable.

[0036] Furthermore, it is preferable that the barrel distortion caused by the above-described configuration be corrected within the zoom lens, or even within the imaging device. By effectively correcting the distortion, it is possible to improve the optical performance of the zoom lens L0.

[0037] Furthermore, it is preferable to set the numerical ranges of conditional expressions (1) and (2) as shown in the following conditional expressions (1a) and (2a). -12.0 <Distw<-4.9 (1a) 10.0 < ωw < 24.5 (2a)

[0038] Furthermore, it is more preferable to set the numerical ranges of conditional expressions (1) and (2) as shown in the following conditional expressions (1b) and (2b). -9.0 <Distw<-5.0 (1b) 15.0 < ωw < 24.0 (2b)

[0039] By setting the numerical range to the conditional equations (2a) and (2b), it is possible to suppress the occurrence of various aberrations such as field curvature and astigmatism at the wide-angle end.

[0040] Furthermore, it is preferable that the zoom lens L0 in each embodiment satisfies one or more of the following conditional expressions (3) to (9). -2.00<(r211+r1N2) / (r211-r1N2)<1.00 (3) 1.00 <fLR / f3<9.00 (4) -7.00 <f1 / f2<-2.50 (5) 1.00 <fLR×LS2 / (f1×LS1)<3.00 (6) -1.00<(r212+r211) / (r212-r211)<1.00 (7) 0.50 <f21 / f2<2.00 (8) -4.00<(1-β2T)×β2RT<-1.20 (9)

[0041] Here, r1N2 is the radius of curvature of the image-side lens surface of the lens positioned closest to the image in the first lens group L1. r211 is the radius of curvature of the object-side lens surface of the lens positioned closest to the object in the second lens group L2. f3 is the focal length of the third lens group L3. fLR is the focal length of the final lens group LR. f1 is the focal length of the first lens group L1. f2 is the focal length of the second lens group L2. LS1 is the distance along the optical axis from the object-side lens surface to the aperture diaphragm of the lens closest to the object in the zoom lens at the wide-angle end. LS2 is the distance along the optical axis from the aperture diaphragm to the image plane in the zoom lens at the wide-angle end.

[0042] r212 is the radius of curvature of the image-side lens surface of the lens closest to the object in the second lens group L2. f21 is the focal length of the lens closest to the object in the second lens group L2. β2T is the lateral magnification of the second lens group L2 when the zoom lens is in focus at the telephoto end. β2RT is the combined lateral magnification of the lens groups from the third lens group L3 to the final lens group LR when the zoom lens is in focus at the telephoto end.

[0043] The technical meanings of conditional expressions (3) through (9) are explained below.

[0044] Conditional equation (3) defines the relationship between the radius of curvature of the image-side lens surface of the lens positioned furthest towards the image in the first lens group L1 and the radius of curvature of the object-side lens surface of the lens positioned furthest towards the object in the second lens group L2. If the upper limit of conditional equation (3) is exceeded, barrel distortion at the wide-angle end generated in the first lens group L1 is suppressed, and the position of the exit pupil shifts towards the image side. As a result, the ray height of off-axis rays incident on the second lens group L2 increases, and the lens diameter of the second lens group L2 becomes larger, which is undesirable. If the lower limit of conditional equation (3) is exceeded, the curvature of the object-side lens surface of the lens furthest towards the object in the second lens group L2 becomes too strong, and spherical aberration and coma aberration occur strongly at the telephoto end, which is undesirable.

[0045] Conditional equation (4) specifies the ratio of the focal length of the third lens group L3 to the focal length of the final lens group LR. If the ratio exceeds the upper limit of conditional equation (4), the positive refractive power of the final lens group LR becomes too weak. As a result, the ray height of the off-axis rays incident on the second lens group L2 increases, and the lens diameter of the second lens group L2 becomes larger, which is undesirable. If the ratio falls below the lower limit of conditional equation (4), the positive refractive power of the third lens group L3 becomes too weak. As a result, the diameter of the lens group positioned closer to the image than the third lens group L3 becomes larger, which is undesirable.

[0046] Conditional equation (5) specifies the ratio of the focal length of the first lens group L1 to the focal length of the second lens group L2. If the ratio exceeds the upper limit of conditional equation (5), the refractive power of the first lens group L1 becomes too strong compared to the second lens group L2. This is undesirable because it becomes difficult to adequately correct spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end. If the ratio falls below the lower limit of conditional equation (5), the refractive power of the second lens group L2 becomes too strong compared to the first lens group L1. This is undesirable because it results in strong coma aberration and lateral chromatic aberration at the wide-angle end.

[0047] Condition (6) relates to the focal length of the first lens group L1, the focal length of the final lens group LR, and the arrangement of the aperture diaphragm at the wide-angle end. If the upper limit of condition (6) is exceeded, the positive refractive power of the final lens group LR, which is positioned closer to the image than the diaphragm at the wide-angle end, decreases, and barrel distortion is suppressed. As a result, the ray height of off-axis rays incident on the second lens group L2 increases, and the lens diameter of the second lens group L2 increases, which is undesirable. If the lower limit of condition (6) is exceeded, the positive refractive power of the lens group positioned closer to the object than the diaphragm at the wide-angle end decreases, and the diameter of the lens group positioned closer to the image than the diaphragm increases, which is undesirable.

[0048] Conditional equation (7) defines the relationship between the radius of curvature of the object-side lens surface and the image-side lens surface in the lens positioned closest to the object in the second lens group L2. If the upper limit of conditional equation (7) is exceeded, the refractive power of the object-side lens surface becomes too strong compared to the image-side lens surface in the lens positioned closest to the object in the second lens group L2. This is undesirable because it makes it difficult to correct coma aberration throughout the entire zoom range. If the lower limit of conditional equation (7) is fallen below, the refractive power of the object-side lens surface becomes too weak in the lens positioned closest to the object in the second lens group L2, suppressing barrel distortion at the wide-angle end. This is undesirable because it increases the ray height of off-axis rays incident on the second lens group L2, resulting in a larger lens diameter for the second lens group L2.

[0049] Condition (8) specifies the ratio of the focal length of the lens in the second lens group L2 that is closest to the object to the object to the focal length of the second lens group L2. If the upper limit of condition (8) is exceeded, the positive refractive power of the lens in the second lens group that is closest to the object becomes too weak, suppressing barrel distortion at the wide-angle end. As a result, the ray height of off-axis rays incident on the second lens group L2 increases, and the lens diameter of the second lens group L2 becomes larger, which is undesirable.

[0050] If the value falls below the lower limit of condition (8), the positive refractive power of the second lens group becomes too strong. This is undesirable because it results in strong coma, axial chromatic aberration, and lateral chromatic aberration at the wide-angle end.

[0051] Conditional equation (9) defines the eccentricity sensitivity of the second lens group L2 when it is in focus at infinity at the telephoto end. Here, when the second lens group L2, which is in focus on an object at infinity at the telephoto end, is moved perpendicular to the optical axis, the amount of movement of the second lens group L2 is ΔL, and the amount of image movement on the image plane is ΔI, then the eccentricity sensitivity TS is expressed by the following equation. TS = ΔI / ΔL

[0052] If the upper limit of condition (9) is exceeded, the positive refractive power of the second lens group becomes too weak. As a result, the ray height of the off-axis light rays incident on the second lens group L2 increases, and the lens diameter of the second lens group L2 becomes larger, which is undesirable. If the lower limit of condition (9) is exceeded, the positive refractive power of the second lens group becomes too strong. As a result, coma aberration, axial chromatic aberration, and lateral chromatic aberration occur strongly at the telephoto end, which is undesirable.

[0053] Furthermore, it is more preferable to set the numerical ranges of conditional expressions (3) to (9) as shown in the following conditional expressions (3a) to (9a). -1.90<(r211+r1N2) / (r211-r1N2)<0.00 (3a) 1.30 <fLR / f3<5.00 (4a) -6.00 <f1 / f2<-3.00 (5a) 1.20 <fLR×LS2 / (f1×LS1)<2.50 (6a) -0.90<(r212+r211) / (r212-r211)<0.00 (7a) 0.80 <f21 / f2<1.80 (8a) -3.00<(1-β2T)×β2RT<-1.50 (9a)

[0054] Furthermore, it is more preferable to set the numerical ranges of conditional expressions (3) to (9) as shown in the following conditional expressions (3b) to (9b). -1.80<(r211+r1N2) / (r211-r1N2)<-0.50 (3b) 1.40 <fLR / f3<3.50 (4b) -5.50 <f1 / f2<-3.50 (5b) 1.30 <fLR×LS2 / (f1×LS1)<2.30 (6b) -0.70<(r212+r211) / (r212-r211)<-0.30 (7b) 0.90 <f21 / f2<1.70 (8b) -2.80<(1-β2T)×β2RT<-1.70 (9b)

[0055] By setting the numerical range to the conditional equations (3a) and (9b), it is possible to suppress the occurrence of various aberrations such as field curvature and astigmatism at the wide-angle end.

[0056] Next, we will describe the details of the configuration of the zoom lens L0 in each embodiment. Note that for the zoom lens L0 in each embodiment, the same configuration as that of the zoom lens L0 in Embodiment 1 will not be explained.

[0057] [Examples 1 and 2] The zoom lens L0 of Examples 1 and 2 consists of a first lens group L1 having positive refractive power, a second lens group L2 having negative refractive power, a third lens group L3 having positive refractive power, an intermediate group LM, and a final lens group LR having positive refractive power, arranged in order from the object side to the image side. The intermediate group LM consists of a fourth lens group L4 having negative refractive power, a fifth lens group L5 having positive refractive power, and a sixth lens group L6 having negative refractive power.

[0058] During zooming from the wide-angle end to the telephoto end, the second lens group L2 and the final lens group LR remain stationary relative to the image plane, while the first lens group L1 moves toward the object relative to the image plane. This reduces the ray height of the on-axis marginal rays incident on the second lens group L2 at the telephoto end, allowing the second lens group L2 to have a smaller diameter. Furthermore, during zooming from the wide-angle end to the telephoto end, the third lens group L3 and the fifth lens group L5 move along the same trajectory. This simplifies the zooming mechanism, making it easier to miniaturize zoom lenses.

[0059] When focusing from infinity to near distance, the fourth lens group L4 moves towards the object, and the sixth lens group L6 moves towards the image. The movement of multiple lens groups makes it easier to suppress variations in aberrations that occur during focusing. Furthermore, by moving a lens group with a small diameter and negative refractive power during focusing, the diameter of the zoom lens can be reduced.

[0060] Furthermore, for vibration damping, the second lens group L2 moves in a direction that includes a component perpendicular to the optical axis. By moving the second lens group L2, which has a smaller diameter compared to the other lens groups, the vibration damping mechanism can be miniaturized, making the zoom lens smaller.

[0061] [Example 3] The zoom lens L0 of Example 3 consists of a first lens group L1 having positive refractive power, arranged in order from the object side to the image side; a second lens group L2 having negative refractive power; a third lens group L3 having positive refractive power; an intermediate group LM; and a final lens group LR having positive refractive power. The intermediate group LM consists of a fourth lens group L4 having negative refractive power.

[0062] When focusing from infinity to near distance, the fourth lens group L4 moves toward the image plane. By moving a group with a small diameter and negative refractive power during focusing, the diameter of the zoom lens can be reduced.

[0063] In the zoom lens L0 according to Example 3, the fourth lens group L4 has one positive lens and one negative lens. This makes it possible to suppress fluctuations in axial chromatic aberration and lateral chromatic aberration that occur during focusing.

[0064] In the zoom lens L0 according to Example 3, the third lens group L3 has four positive lens groups. As a result, the positive refractive power of the third lens group L3 is increased, which suppresses spherical aberration, especially at the wide-angle end.

[0065] [Example 4] The zoom lens L0 of Example 4 consists of a first lens group L1 having positive refractive power, a second lens group L2 having negative refractive power, a third lens group L3 having positive refractive power, an intermediate group LM, and a final lens group LR having positive refractive power, all arranged in order from the object side to the image side. The intermediate group LM consists of a fourth lens group L4 having negative refractive power and a fifth lens group L5 having negative refractive power.

[0066] When focusing from infinity to near distance, the fourth lens group L4 and the fifth lens group L5 are relative to the image plane. imageThe lenses move to the side. By moving multiple lens groups, it becomes easier to suppress the fluctuations in aberrations that occur during focusing. In addition, by moving a group with a small diameter and negative refractive power during focusing, the focusing mechanism can be simplified, allowing for a smaller diameter zoom lens.

[0067] In the zoom lens L0 according to Example 4, the lens positioned closest to the image side among the lenses of the final lens group LR has a positive meniscus shape with a convex surface facing the image side. This makes it possible to suppress chromatic aberration, especially at the wide-angle end.

[0068] [Example 5] The zoom lens L0 of Example 5 consists of a first lens group L1 having positive refractive power, a second lens group L2 having negative refractive power, a third lens group L3 having positive refractive power, an intermediate group LM, and a final lens group LR having positive refractive power, arranged in order from the object side to the image side. The intermediate group LM consists of a fourth lens group L4 having positive refractive power, a fifth lens group L5 having negative refractive power, and a sixth lens group L6 having negative refractive power.

[0069] When focusing from infinity to near distance, the fifth lens group L5 and the sixth lens group L6 move towards the object. The movement of multiple lens groups makes it easier to suppress variations in aberrations that occur during focusing. Furthermore, by moving the small-diameter, negatively refractive group during focusing, the diameter of the zoom lens can be reduced.

[0070] In the zoom lens L0 according to Example 5, the lens positioned closest to the image side among the lenses of the final lens group LR has a negative meniscus shape with a concave surface facing the image side. This makes it possible to suppress field curvature aberration, especially at the wide-angle end.

[0071] [Differentiation] Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of its gist.

[0072] In the zoom lens L0 according to each embodiment, when zooming from the wide-angle end to the telephoto end, the first lens group L1 moves toward the object relative to the image plane, and the second lens group L2 remains stationary relative to the image plane. However, it is not limited to this, and each lens group may move such that the distance between the first lens group L1 and the second lens group L2 increases. For example, when zooming from the wide-angle end to the telephoto end, the second lens group L2 may move toward the image relative to the image plane, and the first lens group L1 may move toward the object relative to the image plane. Alternatively, the second lens group L2 may move toward the object relative to the image plane, and the first lens group L1 may move toward the object relative to the image plane by a larger amount than the amount of movement of the second lens group L2. Or, the first lens group L1 may remain stationary relative to the image plane, and the second lens group may move toward the image relative to the image plane.

[0073] The zoom lens L0 according to each of the embodiments described above may be used in an imaging device that has an image processing function to correct various aberrations (distortion and chromatic aberration). By effectively correcting the various aberrations that occur in the zoom lens L0, it is possible to achieve high optical performance while maintaining a compact size.

[0074] The following shows the numerical values ​​corresponding to the zoom lens L0 in Examples 1 to 5.

[0075] In the surface data for each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the on-axial spacing (distance along the optical axis) between the m-th surface and the (m+1)-th surface. Here, m is the surface number counted from the light incidence side. Furthermore, nd represents the refractive index of each optical element with respect to the d-line, and νd represents the Abbe number of the optical element. Note that the Abbe number νd of a certain material is given by nd, nF, nC, and ng, respectively, when the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), C-line (656.3 nm), and g-line (wavelength 435.8 nm) are nd, nF, nC, and ng, respectively. νd=(nd-1) / (nF-nC) It is represented by

[0076] In each numerical example, d, focal length (mm), F-number, and semi-field angle (°) are all values when the optical system of each example is focused on an infinite object. BF is the back focus, which is the air-equivalent distance from the final lens surface of the lens with refractive power to the image plane. The overall lens length is the value obtained by adding BF to the distance from the surface on the object side to the final lens surface.

[0077] The "*" attached to the surface number means that the surface has an aspherical shape. The aspherical shape is represented by the following formula when x is the displacement amount from the vertex of the surface in the optical axis direction, h is the height from the optical axis in the direction orthogonal to the optical axis, R is the paraxial curvature radius, k is the conic constant, and A4, A6, A8, A10, and A12 are the aspherical coefficients of each order. x = (h , 10 , , , 8 ,

[0078] , , 4 , , , 2 , , , 12 , , 8 , 6 , , , 1 / 2 ,

[0079] , , , , / R) / [1 + {1 - (1 + k)(h / R) 2} 1 / 2 + A4 × h 4 + A6 × h 6 + A 8 × h 8 + A10 × h 10 + A12 × h 12

[0078] Note that "e±XX" in each aspherical coefficient means "×10±XX".

[0079] [Numerical Example 1] Unit: mm Surface Data Surface Number r d nd νd 1 126.433 1.50 1.72047 34.7 2 67.508 8.93 1.​​​​​​​ 7 37.715 4.63 8 -56.686 1.30 1.49700 81.7 9 42.912 4.64 1.90366 31.3 10 -946.232 (variable) 11 (aperture) ∞ 0.48 12 79.782 6.03 1.59522 67.7 13 -78.116 (variable) 14 -36.499 1.20 1.67270 32.1 15 70.747 3.61 2.05090 26.9 16 -595.435 (variable) 17 81.685 6.27 1.49700 81.7 18 -51.527 0.15 19 69.167 7.81 1.53775 74.7 20 -32.977 1.35 1.61340 44.3 21 33.252 0.14 22* 29.719 6.69 1.58313 59.4 23* -150.041 (variable) 24 214.923 1.20 1.61800 63.4 25 34.003 (Variable) 26 -185.456 0.95 1.90525 35.0 27 215.602 1.83 28 103.937 5.06 1.89190 37.1 29 -141.626 41.56 Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4=-1.68734e-06 A 6=-2.63035e-09 A 8= 6.96592e-13 Page 23 K = 0.00000e+00 A 4= 3.67767e-06 A 6=-3.79218e-09 A 8= 9.41782e-12 A10=-1.09116e-14 Various data Zoom ratio 2.83 Wide-angle, Medium, Telephoto Focal length 51.50 85.04 145.50 F-number 2.89 2.89 2.91 Half-angle 22.79 14.14 8.28 Image height 20.53 21.63 21.63 Lens length: 176.15, 208.50, 234.55 BF 41.56 41.56 41.56 d 5 5.16 37.51 63.56 d10 22.15 13.93 4.09 d13 5.24 9.88 14.97 d16 11.92 7.28 2.19 d23 8.53 6.60 2.97 d25 8.82 18.98 32.45 Zoom lens group data Group starting plane focal length L1 1 160.87 L2 6 -43.07 L3 11 67.27 L4 14 -89.40 L5 17 40.10 L6 24 -65.53 LR 26 164.54

[0080] [Numerical Example 2] Unit: mm Surface data Face number rd nd νd 1 110.486 1.50 1.72047 34.7 2 67.323 10.36 1.49700 81.7 3 358.622 0.20 4 104.174 7.56 1.48749 70.2 5 -2248.250 (variable) 6 -120.828 1.45 1.76385 48.5 7 35.216 5.01 8 -63.129 1.30 1.49700 81.7 9 38.472 4.24 1.90366 31.3 10 668.992 (variable) 11 (aperture) ∞ 0.36 12 68.446 6.82 1.49700 81.7 13 -51.002 (variable) 14 -38.580 1.20 1.67270 32.1 15 42.224 4.90 2.05090 26.9 16 -284.561 (variable) 17 78.900 7.87 1.59522 67.7 18 -28.277 1.00 1.67300 38.3 19 37.493 0.65 20 35.429 4.11 1.49700 81.7 21 154.883 0.11 22* 50.719 6.13 1.58313 59.4 23* -50.718 (variable) 24 448.649 1.20 1.61800 63.4 25 38.366 (Variable) 26 -729.285 1.00 1.90525 35.0 27 116.782 2.09 28 88.887 6.45 1.89190 37.1 29 -188.034 44.51 Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4=-5.25447e-06 A 6=-2.10957e-09 A 8=-8.82508e-12 Page 23 K = 0.00000e+00 A 4= 2.26673e-06 A 6=-2.28795e-09 A 8=-1.01735e-11 A10= 8.00333e-15 Various data Zoom ratio 2.83 Wide-angle, Medium, Telephoto Focal length 51.50 84.96 145.50 F-number 2.89 2.89 2.91 Half-angle 22.82 14.29 8.27 Image height 20.45 21.63 21.63 Lens length: 176.16 x 205.72 x 234.56 BF 44.51 44.51 44.51 d 5 5.14 34.70 63.54 d10 21.98 12.26 4.01 d13 2.44 6.30 9.69 d16 9.37 5.51 2.13 d23 9.35 7.92 2.91 d25 7.85 19.00 32.27 Zoom lens group data Group starting plane focal length L1 1 150.97 L2 6 -37.94 L3 11 59.94 L4 14 -219.57 L5 17 50.20 L6 24 -67.96 LR 26 165.36

[0081] [Numerical Example 3] Unit: mm Surface data Face number rd nd νd 1 109.916 1.50 1.72047 34.7 2 66.222 9.14 1.49700 81.7 3 299.512 0.20 4 178.050 5.68 1.59522 67.7 5 -451.039 (variable) 6 -103.769 1.45 1.81600 46.6 7 45.014 5.93 8 -43.071 1.30 1.49700 81.7 9 64.303 3.94 2.05090 26.9 10 -664.889 (variable) 11 (aperture) ∞ 0.46 12 42.562 7.17 1.49700 81.7 13 -384.816 0.30 14 52.730 5.90 1.49700 81.7 15 -708.459 2.67 16 -67.217 1.20 1.62588 35.7 17 58.613 6.80 2.05090 26.9 18 -94.074 1.54 19 -92.784 1.00 1.85478 24.8 20 32.674 0.29 21 30.510 2.48 1.59522 67.7 22 39.431 0.52 23* 34.786 7.27 1.58313 59.4 24* -57.473 (variable) 25 166.726 1.47 1.64850 53.0 26 26.575 2.44 2.05090 26.9 27 32.975 (Variable) 28* -250.008 1.00 1.72000 46.0 29* 157.867 0.97 30 50.059 10.56 1.48749 70.2 31 -85.993 50.21 Image plane ∞ Aspherical data Page 23 K = 0.00000e+00 A 4=-8.35017e-06 A 6=-1.53422e-09 A 8=-1.59483e-11 Page 24 K = 0.00000e+00 A 4= 1.34828e-06 A 6=-1.01836e-10 A 8=-1.63731e-11 A10= 1.04688e-14 Page 28 K = 0.00000e+00 A 4=-2.63360e-06 A 6= 1.02522e-08 A 8= 2.25163e-12 Page 29 K = 0.00000e+00 A 4=-1.60776e-06 A 6= 1.09513e-08 Various data Zoom ratio 2.83 Wide-angle, Medium, Telephoto Focal length 51.50 85.38 145.50 F-number 2.89 2.89 2.91 Half-angle 22.78 14.11 8.28 Image height 19.96 21.63 21.63 Lens length: 176.15 x 214.79 x 236.15 BF 50.21 50.21 50.21 d 5 3.99 42.63 63.99 d10 26.83 18.18 4.07 d24 2.95 2.97 6.63 d27 8.99 17.63 28.07 Zoom lens group data Group starting plane focal length L1 1 163.86 L2 6 -36.73 L3 11 40.87 L4 25 -82.92 LR 28 125.00

[0082] [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 159.158 1.80 1.72047 34.7 2 90.004 9.24 1.49700 81.7 3 -421.124 0.24 4 187.175 3.61 1.61800 63.4 5 788.760 (variable) 6 -130.768 1.74 1.78800 47.4 7 50.668 5.41 8 -46.465 1.56 1.49700 81.7 9 70.007 3.56 2.05090 26.9 10 2846.774 (variable) 11 (aperture) ∞ 0.35 12 63.384 5.99 1.49700 81.7 13 -298.638 0.36 14 43.238 5.90 1.49700 81.7 15 167.085 14.30 16 -46.226 1.40 1.65412 39.7 17 37.166 10.10 1.84666 23.8 18 -60.950 0.38 19 -79.709 1.20 1.85478 24.8 20 26.219 9.45 1.59522 67.7 21 -227.534 0.47 22* 33.438 10.01 1.58313 59.4 23* -55.995 (variable) 24 48.264 1.47 1.80400 46.5 25 27.951 (variable) 26 -42.545 1.00 1.51633 64.1 27 -273.571 (variable) 28* -188.756 0.06 1.53344 52.7 29 -440.914 3.33 2.00069 25.5 30 -82.988 (variable) Image plane ∞ Aspherical data Page 22 K = 0.00000e+00 A 4=-5.22140e-06 A 6=-1.43014e-09 A 8=-1.93715e-12 Page 23 K = 0.00000e+00 A 4= 2.95766e-06 A 6=-3.33083e-09 Page 28 K = 0.00000e+00 A 4= 2.73039e-06 A 6=-4.47790e-10 A 8= 6.51103e-13 Various data Zoom ratio 2.84 Wide-angle, Medium, Telephoto Focal length 61.51 101.60 174.60 F-number 2.89 2.89 2.91 Half-angle 19.37 11.96 6.91 Image height 20.57 21.63 21.63 Lens length: 197.48 x 232.04 x 262.48 BF 37.73 48.93 59.79 d 5 11.89 46.45 76.89 d10 25.99 14.80 3.93 d23 5.95 4.69 0.97 d25 18.18 17.65 20.94 d27 4.80 6.59 7.03 d30 37.73 48.93 59.79 Zoom lens group data Group starting plane focal length L1 1 175.47 L2 6 -40.06 L3 11 45.06 L4 24 -85.35 L5 26 -97.72 LR 28 121.19

[0083] [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 104.296 1.80 1.77047 29.7 2 76.349 9.34 1.49700 81.7 3 -1745.623 0.24 4 609.108 2.92 1.43875 94.7 5 -994.784 (variable) 6 -167.311 1.70 1.58913 61.1 7 42.179 7.43 8 -35.349 1.55 1.49700 81.7 9 79.919 5.04 1.84666 23.8 10 -1540.602 2.50 11 (aperture) ∞ (variable) 12 91.759 6.75 1.49700 81.7 13 -116.434 0.36 14 89.426 6.13 1.49700 81.7 15 -196.104 1.29 16 68.660 11.91 1.62041 60.3 17 -51.465 1.40 1.90525 35.0 18 461.284 (variable) 19 -129.956 1.20 1.72047 34.7 20 33.738 5.87 1.71300 53.9 21 136.933 0.48 22 102.641 3.92 1.87070 40.7 23 -212.291 0.50 24* 208.050 4.21 1.58313 59.4 25* -77.394 (variable) 26 2043.885 5.05 1.84666 23.8 27 -37.930 1.35 1.80100 35.0 28 55.708 (variable) 29 -254.783 1.00 1.77250 49.6 30 105.960 (variable) 31 48.353 9.53 1.64000 60.1 32 -52.044 6.61 33* -33.014 1.75 1.80400 46.5 34* -86.725 37.71 Image plane ∞ Aspherical data Page 24 K = 0.00000e+00 A 4=-2.99882e-06 A 6=-1.96238e-09 A 8=-3.78022e-13 Page 25 K = 0.00000e+00 A 4= 3.33264e-08 A 6=-2.51128e-09 Page 33 K = 0.00000e+00 A 4=-3.99455e-06 A 6= 6.52892e-09 A 8= 4.71708e-12 Page 34 K = 0.00000e+00 A 4=-4.13066e-06 A 6= 5.73681e-09 Various data Zoom ratio 2.61 Wide-angle, Medium, Telephoto Focal length 66.97 99.83 174.59 F-number 2.89 2.89 2.91 Half-angle 17.90 12.23 6.90 Image height 20.50 21.58 21.63 Lens length: 197.87 238.18 262.87 BF 37.71 37.71 37.71 d 5 12.06 52.36 77.06 d11 20.00 15.68 0.96 d18 4.03 2.64 8.05 d25 2.29 0.93 5.42 d28 18.78 26.06 30.92 d30 1.19 0.97 0.94 Zoom lens group data Group starting plane focal length L1 1 191.29 L2 6 -36.12 L3 12 49.79 L4 19 80.28 L5 26 -78.57 L6 29 -96.76 LR 31 76.57

[0084] The values ​​corresponding to conditional expressions (1) to (9) in each numerical example are shown in Table 1 below.

[0085] [Table 1]

[0086] [Imaging device] Next, an embodiment of a digital still camera (imaging device) 10 using the optical system of the present invention as an imaging optical system will be described with reference to Figure 11. In Figure 11, 11 is an imaging optical system composed of any of the zoom lenses L0 according to Embodiments 1 to 5. 12 is an image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor, which is built into the camera body 13 and performs imaging by receiving the optical image formed by the imaging optical system 11 and performing photoelectric conversion. The camera body 13 may be a so-called single-lens reflex camera with a quick-return mirror, or a mirrorless camera without a quick-return mirror.

[0087] Each embodiment disclosed includes the following configuration:

[0088] (Composition 1) It consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, an intermediate group having one or more lens groups, and a final lens group with positive refractive power, all arranged in order from the object side to the image side. In a zoom lens in which the spacing between adjacent lens groups changes during zooming, The lens in the second lens group that is positioned closest to the object has a concave surface facing the object. When zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases. When the amount of distortion at the wide-angle end is Distw[%] and the maximum half-angle at the wide-angle end is ωw[degrees], -20.0 <Distw<-4.5 0.1 < ωw < 25.0 A zoom lens characterized by satisfying the following conditional equation.

[0089] (Configuration 2) When the radius of curvature of the image-side lens surface of the lens located furthest towards the image among the lenses in the first lens group is r1N2, and the radius of curvature of the object-side lens surface of the lens located furthest towards the object among the lenses in the second lens group is r211, -2.00<(r211+r1N2) / (r211-r1N2)<1.00 A zoom lens according to configuration 1, characterized in that it satisfies the following condition.

[0090] (Composition 3) When the focal length of the third lens group is f3 and the focal length of the final lens group is fLR, 1.00 <fLR / f3<9.00 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditional expression.

[0091] (Composition 4) When the focal length of the first lens group is f1 and the focal length of the second lens group is f2, -7.00 <f1 / f2<-2.50 A zoom lens according to any one of configurations 1 to 3, characterized by satisfying the following conditional expression.

[0092] (Composition 5) The zoom lens has an aperture diaphragm, When the focal length of the first lens group is f1, the focal length of the final lens group is fLR, the distance along the optical axis from the object-side lens surface of the zoom lens closest to the object at the wide-angle end to the aperture diaphragm is LS1, and the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end is LS2, 1.00 <fLR×LS2 / (f1×LS1)<3.00 A zoom lens according to any one of configurations 1 to 4, characterized by satisfying the following conditional expression.

[0093] (Composition 6) The zoom lens according to any one of configurations 1 to 5, characterized in that the intermediate group has one or more lens groups with negative refractive power.

[0094] (Composition 7) The zoom lens according to any one of configurations 1 to 6, characterized in that the second lens group is immovable for zooming.

[0095] (Composition 8) A zoom lens according to any one of configurations 1 to 7, characterized in that the lens located closest to the object among the lenses included in the second lens group has a negative refractive power.

[0096] (Composition 9) When, among the lenses included in the second lens group, the lens positioned closest to the object has a radius of curvature of the object-side lens surface of r211 and a radius of curvature of the image-side lens surface of r212, -1.00<(r212+r211) / (r212-r211)<1.00 A zoom lens according to any one of configurations 1 to 8, characterized by satisfying the following conditional expression.

[0097] (Composition 10) When the focal length of the lens closest to the object among the lenses included in the second lens group is f21, and the focal length of the second lens group is f2, 0.50 <f21 / f2<2.00 A zoom lens according to any one of configurations 1 to 9, characterized by satisfying the following conditional expression.

[0098] (Composition 11) The zoom lens according to any one of configurations 1 to 10, characterized in that the second lens group moves in a direction including a component perpendicular to the optical axis for image shake correction.

[0099] (Composition 12) When the lateral magnification of the second lens group at the telephoto end of the zoom lens is β2T, and the combined lateral magnification of the lens groups from the third lens group to the final lens group at the telephoto end of the zoom lens is β2RT, -4.00 < (1-β2T) × β2RT < -1.20 A zoom lens according to any one of configurations 1 to 11, characterized by satisfying the following conditional expression.

[0100] (Composition 13) It consists of a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate group consisting of one or more lens groups, and a final lens group with positive refractive power, all arranged sequentially from the object side to the image side. In a zoom lens in which the spacing between adjacent lens groups changes during zooming, The second lens group is a zoom lens characterized by having a positive lens.

[0101] (Composition 14) An imaging device characterized by having a zoom lens described in any one of configurations 1 to 13, and an image sensor that images an object through the zoom lens. [Explanation of Symbols]

[0102] L0 Zoom Lens L1 First lens group L2 Second lens group L3 Third lens group LM intermediate group LR Final Lens Group SP aperture diaphragm IP image plane

Claims

1. It consists of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, an intermediate group consisting of one or more lens groups, and a final lens group with positive refractive power, all arranged in order from the object side to the image side. In a zoom lens in which the spacing between adjacent lens groups changes during zooming, The zoom lens has an aperture diaphragm, The first lens group consists of a negative lens, a positive lens, and a positive lens arranged in order from the object side. The aforementioned intermediate group includes a group of lenses with one or more negative refractive powers. When the maximum half-angle at the wide-angle end is ωw [degrees], the focal length of the first lens group is f1, the focal length of the final lens group is fLR, the distance along the optical axis from the object-side lens surface of the lens closest to the object at the wide-angle end to the aperture diaphragm is LS1, the distance along the optical axis from the aperture diaphragm to the image plane at the wide-angle end is LS2, the focal length of the third lens group is f3, and the focal length of the second lens group is f2, 0.1<ωw<25.0 1.20 ≤ fLR × LS² / (f1 × LS1) < 3.00 1.00<fLR / f3<5.00 -7.00<f1 / f2<-3.00 A zoom lens characterized by satisfying the following conditional equation.

2. When the amount of distortion at the wide-angle end of the zoom lens is Distw [%], -20.0<Distw<-4.5 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

3. When the radius of curvature of the image-side lens surface of the lens located furthest towards the image among the lenses included in the first lens group is r1N2, and the radius of curvature of the object-side lens surface of the lens located furthest towards the object among the lenses included in the second lens group is r211, -2.00<(r211+r1N2) / (r211-r1N2)<1.00 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

4. The zoom lens according to claim 1, characterized in that the second lens group is immovable for zooming.

5. The zoom lens according to claim 1, characterized in that the lens included in the second lens group that is positioned closest to the object has a negative refractive power.

6. When, among the lenses included in the second lens group, the lens positioned closest to the object has a radius of curvature of the object-side lens surface of r211 and a radius of curvature of the image-side lens surface of r212, -1.00<(r212+r211) / (r212-r211)<1.00 The zoom lens according to claim 5, characterized in that it satisfies the following condition.

7. When the focal length of the lens positioned closest to the object among the lenses included in the second lens group is f21, 0.50<f21 / f2<2.00 The zoom lens according to claim 5, characterized in that it satisfies the following condition.

8. The zoom lens according to claim 1, characterized in that the second lens group moves in a direction including a component perpendicular to the optical axis for image shake correction.

9. When the lateral magnification of the second lens group at the telephoto end of the zoom lens is in focus at infinity, and the combined lateral magnification of the lens groups from the third lens group to the final lens group at the telephoto end of the zoom lens is in focus at infinity, then, -4.00<(1-β2T)×β2RT<-1.20 The zoom lens according to claim 8, characterized in that it satisfies the following condition.

10. An imaging device characterized by having a zoom lens according to any one of claims 1 to 9 and an image sensor that images an object through the zoom lens.

Images